Phil L wrote:

The '1 in 40' rule only applied to soil - rainwater can go at any angle,
but even soil drains are now no longer subject to the '1 in 40' rule.....the
idea was that ****, travelling at velocity, would splatter up the sides of
inspection chambers and the like, then when it set, it would build up into a
blockage, they now don't insist on this as slow moving turds cause blockages
themselves.

I thought the justification was that if the angle is too steep,
the fluids drain too fast, leaving the solids stranded. A lower
angle was thought to keep the solids afloat and moving.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.